Nonlinear ion-acoustic double-layers in electronegative plasmas with electrons featuring Tsallis distribution

• Ion acoustic double-layers are studied in an electronegative nonextensive plasma.
• A generalized Korteweg–de Vries equation with a cubic nonlinearity is derived.
• Different types of electronegative plasmas inspired from the experimental studies of Ichiki et al. are discussed.
• The influence of electron nonextensivity on ion-acoustic double-layers is examined.

Weakly nonlinear ion-acoustic (IA) double-layers (DLs), which accompany electronegative plasmas composed of positive ions, negative ions, and nonextensive electrons are investigated. A generalized Korteweg–de Vries equation with a cubic nonlinearity is derived using a reductive perturbation method. Different types of electronegative plasmas inspired from the experimental studies of Ichiki et al. (2001) are discussed. It is shown that the IA wave phase velocity, in different mixtures of negative and positive ions, decreases as the nonextensive parameter qq increases, before levelling-off at a constant value for larger qq. Moreover, a relative increase of QQ involves an enhancement of the IA phase velocity. Existence domains of either solitary waves or double-layers are then presented and their parametric dependence is determined. Owing to the electron nonextensivity, our present plasma model can admit compressive as well as rarefactive IA–DLs.